Heavy-grease dispenser



Oct. 9, 1962 H. E. BALLARD HEAVY-GREASE DISPENSER Filed Sept. 6, 1960INVENTOR: 14 52/144 IV 5. [MM/12D A TTORNEKS United States Patent3,057,521 HEAVY-GREASE DISPENSER Herman E. Ballard, 2840 Claremont Ave.,Berkeley, Calif.

Filed Sept. 6, 1960, Ser. No. 54,243 Claims. (Cl. 222-262) Thisinvention relates to and in general has for its object the provision ofa pneumatic cylinder and associated grease cartridge for dispensingheavy greases.

Presently, heavy greases are marketed in cylindrical cartridges forinsertion into a ram or cylinder from which a conventional grease guntakes its feed. The cartridges are in the form of a tin can and as aresult of the unequal pressures to which the interior and exterior ofthe cans are subjected during the operation of the ram, many cans arecrushed or otherwise damaged, with the result that air is entrained inthe grease and proper dispensing thereof is not attained.

More specifically, one of the objects of this invention is the provisionof a grease cartridge and associated ram or cylinder so constructed andarranged that any differential pressure to which the exterior andinterior of the cartridge is subjected can be readily withstood by thecartridge without damage thereto.

Another object of this invention is the provision of a ram or cylinderand an associated grease cartridge wherein the diameter of the cartridgeis such that it will fit into the cylinder with positive clearance andcan therefore be subjected to the cylinder pressure on all of itssurfaces and then sealed against the internal head of the cylinder by anadditional increment of mechanical pressure applied only to the closedend of the grease cartridge.

A further object of this invention is the provision of a greasecartridge for use in the combination above described, comprising acylindrical can sealed at its bottom by an axially movable piston discand provided at its top with a removable lid or cap.

The invention possesses other advantageous features, some of which, withthe foregoing, will be set forth at length in the following descriptionwhere that form of the invention which has been selected forillustration in the drawings accompanying and forming a part of thepresent specification is outlined in full. In said drawings, one form ofthe invention is shown, but it is to be understood that it is notlimited to such form, since the invention as set forth in the claims maybe embodied in other forms.

Referring to the drawings:

FIG. 1 is a mid longitudinal section taken through a ram, greasecartridge, and grease gun embodying the objects of my invention.

FIG. 2 is a side elevation of the grease cartridge shown in section inFIG. 1, with a portion thereof broken away to better illustrate itsconstruction.

The ram illustrated in FIG. 1 and generally designated by the referencenumeral 1 includes an outer cylinder head 2 provided with a central bore3 and a counterbore 4. Mounted in the counterbore 4 is a bearing bushing5 sealed to the cylinder head 2 by a recessed O ring 6. Holding thebushing 5 is a snap ring '7.

Seated on the undercut inner end 8 of the cylinder head 2 and sealedthereto by a recessed O ring 9 is a cylinder sleeve 11. Although notshown, the sleeve is secured to the head 2 by any suitable meansrequired to withstand the pressures herein involved.

Hinged to the opposite end of the sleeve 11 by a hinge pin 12 is a door13 formed with a central, outwardly converging grease port 14. Recessedin the door is an O ring 15 arranged to seal against the enlarged endwall 16 3,057,521 Patented Oct. 9, 1962 2 ametrically opposite the hingepin 12 is a locking bolt 18 receivable in a keeper notch 19 formed inthe door 13. Threaded on the outer end of the bolt 18 is a nut 21serving to clamp the door closed and sealed against the open end of thesleeve 11.

Secured to the outer face of the door 13 by bolts 22 or formed integraltherewith is a conventional grease gun 23 mounting and operated by aconventional pneumatic pump or motor 24. Sealing the gun 23 to the outerface of the door 13 is an O ring 25 recessed in the door around thegrease port 14. The port 14 registers with the intake port 26 of thegrease gun which in turn communicates with the piston bore 27 of the gunthrough a cross bore 28. Extending through the outer face of the greasegun 23 is a grease outlet bore 29 communicating with the piston bore 27through a downwardly opening spring biased check valve 31. Operating inthe piston bore 27 is a piston 32 arranged to be reciprocated in theusual fashion by the pneumatic pump or motor 24.

Fastened to the left end of the cylinder head 2 over anoutwardly'extending cylinder head flange 34 and sealed thereto by an 0ring 35 is a cylinder sleeve 36. Slidable through the bearing bushing 5and sealed thereto by an O ring 37 is a piston stem 38. Here it shouldbe particularly noted that an annular passageway 39 is defined by thebore 3 and the adjacent cylindrical surface of the piston stem 38.

Mounted on the right-hand end of the stem 38 and secured thereto by arecessed nut 41 is a piston 42 having positive clearance with the sleeve11. Recessed in the reduced left-hand end of the stem 38 within theconfines of the piston 42 is an 0 ring 43 serving to seal these twomembers together.

Threaded on the left-hand end of the stem 38 is a small piston 44 andrecessed therein is a gasket ring 45 having a running fit with thecylinder sleeve 36. Fixed to and closing the left end of the sleeve 36is a plug or cap 46 sealed to the sleeve by an O ring 47.

Formed in the plug 46 is a tapped bore 48 arranged to communicatethrough lines 49 and 51 with a conventional four-way air valve 52. Thevalve 52 serves to selectively connect the line 51, and therefore theline 49, either with a source 53 of high-pressure air or with an exhaustport or line 54.

Provided in the cylinder head 2 is a tapped bore 56 communicating at itsinner end with a passagewy 57 leadingto the interior of the sleeve 11.Connected to the outer end of the tapped bore 56 is a line 58 com-'municating with the line 51 and which, by means of the valve 52, can beselectively connected with the source 53 of high-pressure air or withthe exhaust line 54.

The line 51 also connects with the air pump or motor 24 through anair-regulating valve 59 and a duct 59a.

Also provided in the cylinder head 2 is a tapped bore 60 communicatingat its inner end with the passageway 39 and connected at its outer endwith a line '61 leading to the valve 52. In one position of the valve 52the line 61 is placed in communication with the high-pressure line 53,this occurring when the line 51 is placed in communication with theexhaust line 54.

As illustrated in FIG. 1, the ram above described is arranged todispense grease from a grease cartridge 63. The cartridge 63 as shown inFIGS. 1 and 2 consists essentially of a cylindrical tinplate shell orcasing 64 having an outer diameter substantially less than the innerdiameter of the sleeve 11 so as to leave an air passageway 65 betweenthe cartridge casing 64 and the ram sleeve 11.

Closing the bottom end of the cartridge casing 64 and slidable therein,piston fashion, is a plastic disc or piston 66 provided with a bearingflange 67 having a running fit with the interior walls of the casing.Backing the disc or piston 66 is a metal stifiening disc 68 recessedwithin the left-hand end of the piston 66.

Secured to the righthand end of the cartridge casing 64 is an annularmetal ring or top 69 formed with an inner peripheral bead 71 of adiameter substantially equal to the diameter of the inner end of thecylinder head outlet port 14.

Crimped over the bead 71 (FIG. 2) is a removable can top or lid 72. Asshown in FIG. 1, when the cartridge 64 is in its dispensing or operativeposition within the ram, its annular top 69 seats on an annular land '73formed on the inner side of the door 13 and is sealed thereto by an Oring 74 recessed in the door.

Preparatory to charging the ram 1 with a cartridge 63, the door 13 islocked against the open end of the ram sleeve 11 and the control valveis placed in a position wherein the lines 53 and 61 are interconnectedand the line 51 is connected with the exhaust line 54. Highpressure airthen passes into the cylinder head bore 60 and through the passageway 39into the sleeve 36 and against the inner end of the small piston 44. Thestem 38 and the parts connected thereto are thus moved to the left. Inthis position of the valve 52 the left end of the sleeve 36 exhausts toatmosphere through the bore 48, the line 49, the line 51, the valve 52and the exhaust line 54. The piston 42, having thus been moved to theleft end of the sleeve 11, the door 13 is opened and the ram is ready tobe charged with a cartridge.

The lid or cap 72 of a cartridge 63 is then removed and the openedcartridge is inserted into the sleeve 11, and the door 13 closed andlocked. In this condition of the ram and cartridge, the cartridge iscompletely surrounded by air under atmospheric pressure.

The valve 52 is then turned to its dispensing position whereby thehigh-pressure line is placed in communication with the line 51.High-pressure air then passes through the line 49 into the left end ofthe sleeve 36 behind the piston 44. Simultaneously high-pressure airpasses through the line 58 into the left end of the sleeve 11 behind thepiston 42 and through the regulating valve 59 into the pneumatic pump ormotor 24. By reason of the passageway 65, high-pressure air within thesleeve 11 completely surrounds the cartridge 63 and subjects every partof it, including its ends, to the line pressure. Simultaneously the linepressure within the left end of the small sleeve 36 operates on the endof the small piston 44, thus causing the large piston 42 to push thecartridge 63 to the right and to seal its annular end or top 69 againstthe ring 74. Although all of the surfaces of the cartridge are subjectedto the line pressure, it is to be particularly noted that the cartridgepiston 66, in addition to being subjected to the line pressure which istransmitted to it through the piston 42, is simultaneously subjected toa force created on the rear end of the piston 44 and transmitted to thepiston 42 through the piston stem 38. However, since the area of thesmall piston 44 is much smaller than the area of the large piston 42,the supplementary force due to the piston 44 is only a fraction of theforce due to the line pressure acting on the large piston 42. It is theforce resulting from the small piston 44 that serves to hold thecartridge sealed against the cylinder door 13, and this force is thebursting force to which the can is subjected. The total force to whichthe cartridge piston 66 is subjected (line pressure on the large piston42 plus the line pressure on the small piston 44) should be sufiicientto force the grease through the cartridge when supplemented by theaction of the grease gun 23. When the grease gun piston 32 rises, apartial vacuum is created in the bore 27. The resulting and additionaldifferential pressure imposed on the piston 42 drives the piston 42 tothe right and thereby forces grease from the cartridge through the port14 and the passageway 26 into the pump bore 27 beneath the pump piston32. On the down stroke of the piston 32 an increment of grease is cutoff by the piston and forced by the check valve 31 out the dischargeport 29.

When the cartridge 63 is empty, the door 13 is opened and the valve 52reversed so as to retract the piston 42 and ready it for anothercartridge.

By maintaining all of the surfaces of the cartridge under at least linepressure and subjecting the cartridge piston to this pressure plus theadditional but relatively small pressure resulting from the action ofthe smaller piston 44, the differential pressure to which the inside andoutside of the cartridge is subjected can be maintained well below thebursting pressure of the cartridge, particularly along its seam. Greaseis thus prevented from leaking from the cartridge into the ram sleeve 11and bursting of the cartridge into tight engagement with the sleeve 11is likewise avoided.

In calculating the force exerted by the small piston 44, it should beobserved that during its working stroke its right-hand side is underatmospheric pressure by reason of the fact that the bore communicateswith the atmosphere through the valve 52. The force on the lefthand sideof the piston 44 is equal to the line pressure multiplied by thecross-sectional area of the piston. The force on the opposite side ofthe piston 44 is equal to the area of the piston less thecross-sectional area of the stem 38 multiplied by atmospheric pressure.The total force exerted by the piston 44 during its working stroke istherefore the difference between these two forces, and it is thisdifferential total force which is applied to the large piston 42 inaddition to the force resulting from the line pressure within the sleeve11.

Although dimensions are not here critical, the controlling factorsinclude the pressure required to move the grease through a cartridge ofa given diameter and length, the bursting pressure of the cartridge andthe line pressure available.

Although it is possible to locate the seal ring 74 substantiallyadjacent the periphery of the cartridge capping 64 rather than along thedoor land 73, this would require greater accuracy in the formation ofthe casing end so as to insure a proper seal with the O ring.

I claim:

1. A grease-dispensing system comprising: a first cylinder; a firstcylinder head fixed and sealed to one end of said first cylinder; asecond cylinder head removably secured and sealed to the other end ofsaid first cylinder and provided with a central grease exit port; asecond and smaller cylinder secured and sealed to said first cylinderhead coaxially therewith and extending outwardly therefrom a cap securedand sealed to the free end of said second cylinder; a piston stemextending through said first cylinder head coaxially therewith; meansfor slidably sealing said piston stem to said first cylinder head; afirst piston secured to said stem within said first cylinder and havingpositive clearance therewith; a second piston secured to said sternwithin said second cylinder and having a running fit therewith; meansfor establishing communication between said first cylinder and a pointexternal thereto; and means for establishing communication between theouter end of said second cylinder and a point external thereto.

2. A grease-dispensing system of the character set forth in claim 1wherein the outer diameter of said piston stem is less than the innerdiameter of said second cylinder and wherein means is provided forestablishing communication between the inner end of said second cylinderand a point external thereto.

3. A grease-dispensing system of the character set forth in claim 1wherein a grease cartridge is contained in said first cylinder forwardlyof said first piston, said cartridge including a cylindrical shellloaded with grease and having an outer diameter smaller than the innerdiameter of said first cylinder; a piston closing the rear end of saidcylindrical shell and slidable therein; and means for sealing the openfront end of said cartridge against said sec- 5 ond cylinder head whenthe front end of said cartridge is forced against said second cylinderhead.

4. A grease-dispensing system of the character set forth in claim 1wherein a grease gun is sealed to the outer face of said second cylinderhead and arranged to take its feed through the said exit port in saidsecond cylinder head.

5. A grease-dispensing system of the character set forth in claim 3wherein a grease gun is sealed to the outer face of said second cylinderhead and arranged to take its feed from said cartridge through the saidexit port in said second cylinder head.

References Cited in the file of this patent UNITED STATES PATENTS SchankOct. 14, 1919 Engbrecht Nov. 39, 1926 Grimmersen May 8, 1928 HuntleyDec. 11, 1928 Morse Dec. 22, 1931 Franson Mar. 31, 1942 De Hoog Oct. 27,1942 Spenser Dec. 1, 1953 Wiksten Oct. 26, 1954

